This invention relates to methods for controlling shifting parameters of automatic transmissions which have a planetary gear arrangement with a sun gear, planet gear and a ring gear, in which the mechanical linkage of each set of two of the planetary gear components represents a mechanical gear ratio.
In automatic transmissions, engine power is generally transmitted hydraulically by way of a converter to the input side of the transmission. As a result, the engine speed and the transmission input speed differ, depending on the characteristics of the converter, in accordance with load and road resistance. Consequently, if the individual shifting parameters of the transmission are controlled according to the engine speed, difficulties are encountered in accomplishing the shift sequence in the transmission.
During a change of gears in an automatic transmission, variations of transmitted drive moment take place which greatly affect comfort during shifting. Such variations are caused by, among other things, engine speed variations (speed jump) and the total inertia of the transmission input components.